Hello Folks,
To trouble shoot a short in my dash wiring I have removed all connections at the horn relay – the positive battery lead, the starter, the Holley fuel pump – and reading the voltmeter at the 20v setting across the negative battery post and the grounding frame strap. The starter reads .02v. Add the pump, .05. Everything is clean to that point. But when I attach the alternator to the horn relay, it reads full voltage equivalent to the battery charge.

The alternator is rebuilt, double bench tested and wired per other posts on replacing a generator with an S10 (see attached, thanks Joe P). Is this the correct way to test an alternator?
Steven

 

Anyone? I really don't want to just crank it up and see if it smokes.

 

The wiring looks correct, but the test shows a shorted alt. Is there a spark when the bat cable it touched to the bat terminal.

 

It will read full battery voltage at the horn relay because it's looking for a ground from your horn contact behind the steering wheel to make the horn operate.